How Do You Adjust Cantilever Brakes?

I am finishing up the overhaul of my 90/91 Voyageur. I need to replace the rock hard DIA-COMPE brake pads, so I picked up some Kool Stops for it. But I can't seem to get the blasted things to adjust properly.

There are adjustments for fore/aft, up/down, toe in/out, etc. And, don't forget the straddle cable. When I think I get one of the pads aligned correctly, then I notice the other side is now not contacting the rim evenly.

I've worked on lots of side pull and centerpull brakes, but this is my first time working with cantilever brakes. And, I have another bike with them waiting in the wings.

When you say not contacting the rim evenly, do you mean the distance from pad to rim surface on either side is not even? If so, check the tension on the brakes. Sometimes they need a little tweak after the cantilevers being opened up further than usual. There should be a screw on either side to adjust the tension.

The secret, unfortunately, is to keep trying to get them set up properly until you do!. They are a major pain because of all the variables you already mentioned. That said, they stop well when you find the right combination. Plus once you figure it out, you do get better at it.

Me, I went to mechanical discs on my cross style bike (Not C&V) and will not go back to canti's.......

Try adjusting the position of the post so that the pads are closer to the caliper arm. THere is less distortion of the geometry as the arms swing if the pads are close to the arms. later on, move the pads inward (ike you now have them) to makeup for pad wear. By setting the pads like this, the arms are closer to top ow thier swing so will move up/down less, side-to side more as brakes are applied and it will be easier to keep the pads hitting the rims squarely. THis will also necessitate adjustment of the saddle cable. Shorten saddle cable for more mechanical advantage.

I use a mini glue clamp to hold the pads to the rim as I tension and tighten the cable. I use the same method for all other brake setups (exc disc) and find it works very easily. Once the cable is tight, remove the clamp. Now squeeze the lever HARD, like a panic stop effort. This will do 2 things; 1 ensure the cable is tight enough for...a panic stop and 2 it will generally take just enough slack out of the system to make your pads at just the right distance from the rim (I like to run my pads close to a true rim). As to centering, on cantis that's all about balancing the spring pressure from side to side. Tricky on the brakes you have, but as mentioned there should be a small set screw that adjusts spring tension on the outboard side of the brake pivot.

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the beauty of cantis is that the can be adjusted a million different ways until you get them just right. getting there is sometimes a journey.

in your situation, make sure the hangar is in the middle. squeeze the brake and move the hanger with force until it is at the apex. now if your pads are set up with the same amount of post showing and they are still off, adjust the tension screw that is on one of the sides. screw it in to move that brake outward, screw out to move it in.

there's other things you can do too, but i think that should probably solve it. i would reverse your hanger for looks, and maybe spray a little silicone in the hanger for lubrication.

I use a carpenter clamp to hold the pads against the rim with a thin piece of cardboard as a shim under the back end of the shoe to provide toe in. Then tighten the posts, install straddle wire and hangar, pull cable somewhat tight, tighten fixing bolt, release clamp and see what you got. If necessary readjust cable. I find them relatively easy, maybe from using them on mountain bikes in the 90's.

I didn't realize adjusting cantis was so finicky. I guess I just got lucky the first time.

They're finicky, but only troublesome if you take them too seriously. I always kinda worked backwards: First get the pads to contact the rim evenly, then set the cable so you get the proper feel at the levers. Once those two are done (and you've got a workable, safe bike at that point) THEN you start worrying about the minutiae of having the pad shafts angled properly, and insuring the pads go thru their arc without ever touching the sidewall in the slightest (more a problem on a mtb than a 'crosser, tourer or hybrid). Make your adjustments in small increments, going from one side to the other.

Once you've done a dozen or so sets, it all becomes natural and permanently ingrained in your fingers.

Syke

"No wonder we keep testing positive in their bicycle races. Everyone looks like they're full of testosterone when they're surrounded by Frenchmen." ---Argus Hamilton

I didn't realize adjusting cantis was so finicky. I guess I just got lucky the first time.

I think you do not realize how lucky you are to have YOUR cantis. Your cantis are not Dia-Compe. They are early shimano canti's design, possible XT SLR (later this design propagated to cheaper groupsets as well). Brilliance of this design is that toe-in is not just one of the degrees of freedom on the 'arm' it is set my a eccentric washer with a 'tooth' on top of it. You can use that 'tooth' or 'arrow' as indicator of how much toe-in you have. If you put brakes together, and it is not right, look, remember where it was, undo and try in a bit different position. After couple tries you will get it just right. And if you are careful, you will just notice its position BEFORE removing old pads, and start from the same position with the new pads.

And Dia-Compy design that started this thread... I personally can not stand it. My problem with it that it does not allow for incremental improvement, and adjustment tends to creep as you tighten the bold. When you undo the holding bolt, pad completely loses its adjustment, and then you start over, hoping for better luck this time.

Modern Tektro 720 do not have this extra adjuster, but I found that they do not change adjustment nearly as much when the bolt is tightened, and that allows to simply clamp them to the rim, tighten, release - DONE.

I know others will tell me that I simply have not mastered Dia-Compe cantis, and they may be right, but I found those simply infuriating.
Yes, I was able to set them up OK. But I never was happy with end result, and each attempt to change the setup was taking lots of time...

On my bike I ended up taking off those darn Dia-Compes and replacing them: in the rear - with modern Tektro 720, in front - with Shimano XT SLR from end of 80s. Not stock, but works like charm. I love cantilevers now and think they are the best brakes design

I may be wrong (probably am!) but I don think the XCEs have the spring tension adjusting screw on the calipers. Instead, there is a thin nut on the brake post stack, on the back side of one of the calipers-- in between the caliper and the frame. You will need a cone wrench to get under there and set the proper tension with that. Most of the time you need to loosen the brake post bolt, set the tension with the cone wrench, and then tighten the bolt down.

I think you do not realize how lucky you are to have YOUR cantis. Your cantis are not Dia-Compe. They are early shimano canti's design, possible XT SLR (later this design propagated to cheaper groupsets as well). Brilliance of this design is that toe-in is not just one of the degrees of freedom on the 'arm' it is set my a eccentric washer with a 'tooth' on top of it. You can use that 'tooth' or 'arrow' as indicator of how much toe-in you have. If you put brakes together, and it is not right, look, remember where it was, undo and try in a bit different position. After couple tries you will get it just right. And if you are careful, you will just notice its position BEFORE removing old pads, and start from the same position with the new pads.

I wasn't aware of this feature when I was installing them, or if I was I've forgotten.
You're saying the toe in is determined at the arm, and not at the pad?
My recollection is the axis of the arm is fixed by the braze-on on the fork/stay. In at least one case the braze-on was bent and I cold-set it back into position.

[edit]
I took a look at my bike and now I see what olek is talking about. I still don't remember if I deliberately used the washer feature to get the brakes dialed in. All of my indicator pointers are pointing nearly straight up.
I just snagged the first set of canti's I could get on Ebay for a good price, I guess I did luck out.

I just finished setting up a set of old Dia-Compe cantis. There is a secret to it. If I or anyone else knows it, we will report. Having set up a lot of MTB brakes, these should have been easy. Took a lot of incremental fumbling. The brakes work great- finally.

Like a few others have stated I find it easier to set up the pads and clamp them to the rim ( I use a small welding vise grip ) and then use my third hand tool to adjust the cables then deal with centering them when done, seems to work every time for me and yes Dia Compe/Suntour's are not as easy as most Shimano units are to set up but most work just as good when done right. I used to hate setting them up before I discovered this method as I have problems with my hands but now it's no problem.

I use a carpenter clamp to hold the pads against the rim with a thin piece of cardboard as a shim under the back end of the shoe to provide toe in. Then tighten the posts, install straddle wire and hangar, pull cable somewhat tight, tighten fixing bolt, release clamp and see what you got. If necessary readjust cable. I find them relatively easy, maybe from using them on mountain bikes in the 90's.

This is the method that I use and it works very well. I also make sure that my adjuster barrel on the levers (if I have them) is adjusted to the center, that way I have some wiggle room on the wire if it needs to be adjusted a bit.

I use a carpenter clamp to hold the pads against the rim with a thin piece of cardboard as a shim under the back end of the shoe to provide toe in. Then tighten the posts, install straddle wire and hangar, pull cable somewhat tight, tighten fixing bolt, release clamp and see what you got. If necessary readjust cable. I find them relatively easy, maybe from using them on mountain bikes in the 90's.

I forgot to mention the toe-in shim. Thanks.
Im still riding 90's vintage ATB's, and still setting up canti's this way.

"Watch out for giants; they are boorish fools with tongues wagging, drunk upon their own words.
They will try to teach you a lesson if given the chance, and you will stumble over their stinking feet."

Yes, that is how I do it for my Tektro 720 - big spring clamp and an old credit card for shim. Worked great the very first time I tried it, and since MTB-style cartridge pads can be replaced without taking off holders, never had to move them again.

With Dia-Compe design the force necessary to tighten pads was making them move each and every time, making whole setup a crap-shoot. At the very least, Dia-Compe 981 behave that way. Their other designs may be better, but I think they are all rather similar.

To cb400bill: glad that you were able to adjust them! I agree, when they are adjusted properly, they are quite decent brakes.